                        ;'(signal_error)
                        [0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0]
                        [(tag-instruction-erc [:exec])]
-                       (for [t (vals button-entrypoints)]
-                         (fn [] (symbol (str "tag_exec_" (str t)))))
+                       ;(for [t (vals button-entrypoints)]
+                       ;  (fn [] (symbol (str "tag_exec_" (str t)))))
                        [(tagged-instruction-erc)]
+                       ;; allow code_append tag macros (taking 2 arguments and returning 1 result)
+                       [(tagged-code-macro-erc 'code_append @global-tag-limit 2 1)]
                        ;(repeat 46 'code_noop)
                        '(boolean_and
                           boolean_dup

   :pop-when-tagging true
   :report-simplifications 0
   :print-history false
   ;:use-bushy-code true
   :use-ultra-no-paren-mutation true
   :problem-specific-report calc-report-with-reset!
  })

   :reproduction-simplifications 10
   :ultra-probability 1.0
   :ultra-alternation-rate 0.005
   :ultra-alignment-deviation 5
   :ultra-mutation-rate 0.005
   :deletion-mutation-probability 0
   :parentheses-addition-mutation-probability 0
